Climate scientists are in consensus.1 The climate is warming and human activities are the drivers, primarily through burning fossil fuels and deforestation. Today we have twice as many hot summers as observed between 1951 and 1980, and 10 percent of the time, average summer temperatures on land are hotter than ever recorded.2 The potential warming first predicted in the mid-1970s is now actual, measurable warming that will radiate out like waves from a boulder dropped in a pond. The resulting climate tsunami will transform human existence radically in unpredictable ways.
Conventional wisdom has, for decades, impeded timely and effective action to reduce emissions of heat-trapping gases. This is because it was assumed that no energy source was available to replace fossil fuels, and because it was believed to be too expensive, despite evidence to the contrary.3,4 Additionally, the immense amount of energy flowing through the global economy is daunting. The average person on earth annually uses 74 million British Thermal Units (BTUs), while the average U.S. person uses 312 million BTUs, 80 percent of which are from fossil fuels.5 Human activities are responsible for the emission of 37 billion metric tons of carbon dioxide, a mind-boggling amount.6 Each pound of carbon dioxide fills a balloon 2.5 feet in diameter, and human activities annually cause the release of 81 trillion such balloons.7 These balloons contain one hundred times more carbon dioxide than the average annual carbon dioxide released from Earth’s volcanoes. 8
Business as usual is in conflict with nature’s rules?human-caused emissions of heat-trapping gases (carbon dioxide and methane being the most important) are making a planet for which we are not adapted.9,10 What are an individual’s choices? A person can carry on, or attempt to live in compliance with nature’s rules. In the words of Margaret Mead, “never doubt that a small group of thoughtful committed citizens can change the world; indeed, it’s the only thing that ever has.”
Individuals do have a major role to play in reducing the use of fossil fuels and in increasing the sequestration of heat-trapping gases, both in their lives and in their communities. In 2007, the Oberlin area had no homes that ran on sunshine and few, if any, architects or builders who had made one. We set out to build a house capable of running on sunshine that had no energy bill. In doing so, we sought to demonstrate that it can be done with off-the-shelf technologies and building techniques at a cost similar to that of houses of the same type and quality with an energy bill. We also strived to create a landscape that respects the topography and local ecology, sequesters carbon, and produces food while being beautiful, pleasant, and affordable.
Trail Magic: creating a positive energy home
“Trail Magic,” the name we gave our home, is a term used by Appalachian Trail thru-hikers to describe their method of hiking the 2,200 miles from Springer Mountain in Georgia to the top of Mount Katahdin in Maine?you just keep walking, overcoming each obstacle as it arises. By asking questions and seeking local advice, we found a real estate agent who guided us to purchase an excellent site. An architect colleague from Connecticut, who had been designing passive solar houses for decades, agreed to do our schematic design. Mary, my wife and an elementary school teacher, learned of a “green” builder while checking out the Oberlin elementary school near our site. We found a local architect reeducating himself to design high performance houses. One step at a time, we assembled a team of professionals with compatible personalities committed to the primary goal of building a high performance house capable of running on sunshine within the constraints of our budget. Actually building Trail Magic, a 1,300 square foot house with a fully conditioned walk-out basement, was not without glitches. In the end, however, the project turned out well, and five years after completion, the team members are friends who work together to help others create houses capable of operating on sunshine.
Details on Trail Magic can be found on my website and in the book I wrote on the project.11,12 Trail Magic is positive energy because more energy is made from onsite sunshine than is used, and climate positive because it uses no fossil fuels and achieves a net removal of carbon dioxide from the atmosphere (Table 1). Based on four years of data, Trail Magic, with its photovoltaic system (PV) that is connected to the grid to allow electricity to flow to and from the grid (net metering) annually produces 5,400 kilowatt hours (kWh), uses 2,800 kWh, and sends 2,600 kWh of carbon-free electricity to the grid for others to use. Trail Magic annually supplements passive solar heating with about one cord of hardwood, harvested on site from dead and storm-downed trees. However, the home can be heated with its pond-source, geothermal heat pump using about 1,500 kWh. It should be noted that heating with an air-tight, efficient woodstove is not the solution for heating most homes because wood is a limited renewable resource, and without proper operation, a woodstove produces particulate matter and other pollutants. 13
** The BTUs given for the electrical energy used by the average household is about one-third the actual value of primary energy used because it takes about three BTUs of fossil fuel energy to generate one BTU of grid electricity. PV electricity is primary energy produced directly from sunlight. This makes Trail Magic even more efficient in total or primary energy use than the table numbers indicate.
The house is well-lighted by sunlight and at other times by annually using less than 100 kWh for indoor lighting, while an average two-person home uses 2,800 kWh. Annual indoor water use is 9,300 gallons, and hot water use is 2,600 gallons. The average two-person home annually uses between 8,000 and 11,000 kWh (not including gas or oil for heating hot water and the house), 50,000 gallons of water and 8,000 gallons of hot water. Trail Magic’s well-below-average usages are indicative of a high-performance home. They are a result of the house’s design, energy efficient appliances, water conserving appliances and fixtures, and resident behavior of using what is needed. [Image A]
Trail Magic has many “upscale” features, including a raised-seam metal roof, cement-fiber siding, superior windows, quartz kitchen counter tops, a tiled shower, sun patio, rain cistern, and custom beams, bookcases, pantry counter top, floors, and shelves made from onsite trees. Cost per square foot of conditioned space was $146 including the PV system, the same cost for a modest well-built custom house in Northeast Ohio that has an energy bill. If the PV is retained, but the upscale features are replaced by standard ones that provide similar performance, the cost becomes $110 per square foot, equivalent to a quality development house in Northeast Ohio with an energy bill. Having no energy bill is, in fact, an annual dividend of at least $2,100 (the cost of energy for an average two-person home in the Unites States) plus income tax savings because these “saved dollars” do not have to be earned and therefore are not taxed. [Image B]
Two important conditions should be noted. First, the team designing and building a house like Trail Magic must have as its primary goal to make the house capable of being positive energy. Second, resident behavior related to energy and resource use will be a key factor in whether a house designed and built for high performance will, in fact, become a positive energy home. For example, keeping house temperature at 72 degrees day and night, taking long showers, leaving lights on in a room when no one is present, and running the dishwasher half empty are not behaviors conducive to resource conservation.
We made several major mistakes, one of which is especially informative about adopting a new technology: does it perform as advertised? Trail Magic’s hot water was initially provided by a solar evacuated-tube hot water system that preheated water in an 80 gallon tank that was then heated to 111 degrees Fahrenheit, if needed, by an electric on-demand hot water heater. Our team believed, because of industry claims and the technology employed, that this was an innovative and cost effective way to provide domestic hot water. To establish the efficacy of this combined system, we calculated the actual solar energy in the hot water we used.12,14 The annual input of solar energy was equivalent to 30 kWh or $3.00 (USD) at $0.10 per kWh. Preheating domestic hot water with an evacuated tube system was a poor investment economically and equally ineffective for reducing carbon emissions. The evacuated tube system was removed after two years. Trail Magic’s hot water is now heated with the electric on-demand heater alone, using annually 360 kWh, valued at $36.00.
The lesson here is to pay attention to the basic economics and physics. How much hot water will be used annually? How much will it cost to heat this amount of water with an on-demand heater? This cost is the maximum that can be saved annually by employing the solar hot water component. In our case, the maximum to be saved was $36.00 (actual savings were $3.00) while the evacuated tube system cost $6,600 and the on-demand heater cost $600. The evacuated tube system was too expensive for heating our domestic hot water and also likely the case for heating domestic hot water in most residences.
Clearly, building a house has a myriad of impacts on the environment that are often difficult to assess. We employed systems thinking and holistic design decisions to resolve conflicts that arose from the individual perspectives of architecture, beauty and aesthetics, building standards and codes, economics, energy and resource use, and environmentally appropriate construction. Design and material decisions rarely have one optimal choice, but rather a preferred choice within the context of the particular project. Nevertheless, our overriding metric was the lifecycle cost measured environmentally and economically with the scale biased toward the environmental side.
Managing waste by reusing and recycling reduces material and energy use. We reused some materials (reclaimed flag stones for the front porch, old cobblestones for the woodstove hearth, and reclaimed stainless steel for the woodbin). Trail Magic had two derelict houses on site, from which we had 150 tons of material (60 percent) reused or recycled. We did the same with 95 percent (8,961 lbs) of our construction waste with the remaining five percent (511 lbs) going to Oberlin’s landfill. In a consumption-based, throw-away society, an individual must make a concerted effort to do the three Rs well: reduce, reuse, recycle. Improving the infrastructure?physically and economically?for reducing, reusing, and recycling materials could significantly decrease the flow of energy and materials during building construction. Building with a prefabricated roof and walls or building a modular house can reduce overall waste, but the total price depends on many factors.15
Other positive energy homes
A quick review of past issues of Home Power Magazine and Solar Today Magazine provides numerous reports of homes that run partially or completely on sunshine.16,17 In overall design, Trail Magic merely replicated?with better materials?Hill Top, a Troy, New York, passive solar home built in 1981 by the Bortons, one of many high- performance houses built across the country over the last three decades. Hill Top has super insulation, triple-paned high-performance windows, and the appropriate square footage of window area on the south side, along with few windows on the north, east, and west sides. The house initially had a tight envelope (floor, walls, and roof), and even after 30 years, its air exchanges per hour are below two under a vacuum of minus 50 Pascals?a standard measure for tightness or air leakage. Trail Magic’s air exchanges per hour were one, while for existing “traditional’’ houses, exchanges would be up to or more than ten.18 Air leakage is important because most heat loss (winter) and gain (summer) is through the envelope via air movement.
facing below-grade sun patio, shading of windows in July, and PV panels on roof.
Many homes across the country are high-performance and potentially positive energy. In 2000 and 2005, the Bortons made improvements to their 2,300 square foot passive solar house by changing from electric to gas hot water; purchasing an energy-efficient refrigerator, freezer, dishwasher, and washing machine; and installing a 4 kW PV system ?for a cost of $15,800, not including subsidies and tax credits. These changes annually saved $2,700, with a payback time of six years, and reducing Hill Top’s net carbon release to less than zero.19
The Stoners in Troy, NY, rehabilitated their conventional 1954, 1,200 square foot house to make it a positive energy home.12,19 They weatherized it (sealed leaks and installed insulation) and took conservation measures (installing compact fluorescent bulbs, a night setback thermostat, a clothes line, and turned off lights and equipment when not in use) that reduced energy use from 121 to 69 million BTUs. The cost was $5,000, and annually saved $1,200, thereby resulting in a payback time of four years. By installing a new boiler, mostly for hot water, an airtight woodstove, and a 3.3 kW PV system for $25,000 (not including subsidies and tax credits), they further reduced net carbon dioxide release to less than zero. A total annual savings of $2,400 for all improvements resulted in a 13 year payback time.
In 2009-2010, eight houses were designed and built in West Tisbury, MA with the purpose of providing residents with houses that could be positive energy homes depending upon resident behavior.20 Four houses of 1,447 square feet had three bedrooms, and the other four with 1,251 square feet had two bedrooms. Both types had full basements, were all electric, and had a 5 kW PV system capable of annually generating 6,250 kWh. The floor plans were identical except for the third bedroom that was an extension on the north side. In the first year, two were positive energy homes using 90 and 91 percent of the energy produced, while the other six used 115, 120, 125, 134, 151 and 172 percent of their PV systems’ output. The overall conclusion from a detailed, yearlong study of the eight households “confirms that performance ultimately comes down to household size and behavior.” People create positive energy homes because the behavior of inhabitants has a huge influence on performance.
Trail Magic and other positive energy homes exhibit four fundamental principles for creating homes appropriate for the 21st century?homes which curtail the emission of heat-trapping gases.12,19 First is size. The house needs to be as small as possible to meet the needs?not necessarily the wants?of inhabitants. The smaller the house, the smaller the amount of resources required for building, the lower the operating energy, and the fewer resources used over the lifecycle of the house. Second, the envelope needs to be as tight as possible and well insulated to minimize the movement of energy through the envelope. Third, the long axis of the house needs to be east-west to permit passive and active solar features. Fourth, residents need to behave in ways that minimize the use of energy and other resources.
Landscape
The Trail Magic site is rectangular, with 235 feet of street frontage. From the road, the property slopes gently south for 840 feet to Plum Creek. The soil is heavy clay with essentially no percolation. This soil type, along with rainfall extremes expected from climate change, made it imperative to design for flooding. A pond was dug south of the house to provide fill to raise the house site so that the first floor would be several feet above grade in the front, and so the city sewer would be accessible. In addition, the ground floor was earth-bermed on three sides for insulation. Furthermore, we could use the pond to raise fish, to have a heat source and sink for the house’s heat pump, and to provide a reservoir for runoff as well as for watering the garden and landscape in times of drought.
Two swales direct the flow of water away from and around the house. From there, the water drains into the pond, or through a small tall-grass prairie and down a meadow into the Plum Creek flood plain. The house and barn roofs drain into a 1,875 gallon cistern for outside water uses, with the overflow going to the pond. The footer drains of the house flow water into two pipes that go downhill to south of the pond where the water enters a swale with heavy vegetation. The east and west corners of the house’s north side and the eastside window-well have vertical drain pipes connected to the footer drains. The below grade sun patio has two drains that feed into the footer drains.
The property north of Trail Magic is flat with overflow draining into the city storm sewer. The properties to the east and west are mostly higher than Trail Magic and drain into the east and west side swales or the area below the pond. In the past five years, we have not experienced an exceptional rain fall. When we did have three inches in less than 12 hours, the swales moved the water away from the house nicely. Below the pond, “rivers” a few feet deep flowed across the flood plain that was half covered in water. Plum Creek came close to overflowing its banks. It remains to be seen how the landscape will handle exceptional rainfalls.
We have planted over 50 trees and shrubs in the 1.5 acres around the house with the goal of a forested front yard that would not need mowing. In the lower three acres, we lumbered 11,000 board feet of finished wood, mostly from ash trees that were fated to succumb to the emerald ash borer. Over one hundred trees?mostly sugar maple, oak, and Osage orange?remain. We are in the process of reforesting the area and removing the worst of the invasive species: multifloral rose (Rose multiflora), buckthorn (Rhamnus catharctica), and Japanese knotweed (Fallopia japonica).
Four years ago, we planted a test plot of 6,000 square feet with tall grass prairie seeds: Indian grass, big blue stem, switch grass, and 19 other flowering prairie plants. This year, we had many tall grass inflorescences, and about 10 other prairie plants flowered among a riot of local species. [Image C] Following this success, over the next few years, we plan to plant about an acre in tall grass prairie to sequester carbon and build soil to capture and flow water slowly, as well as to provide food for birds and habitat for myriad species of invertebrates and microorganisms.
Oberlin soil is dense clay with close to zero percolation thereby requiring amendments to make a vegetable garden. We purchased a truckload of sand, used many truckloads of leaf mulch soil provided by the City of Oberlin, and wood chips from a local arborist along with heavy mulching to establish a 6,000 square foot vegetable garden that produced over 400,000 calories in 2012, or about a third of our annual caloric need. We have a small nascent orchard with blueberry bushes, and apple, pear, and hazelnut trees. The pond has been stocked with bluegills, largemouth bass, and catfish that we expect to begin eating next year. [Image D] Younger and more adventurous homeowners may wish to employ the techniques of permaculture to feed themselves and diversify their landscapes.22
In summary, lessons learned: creating a landscape is an ongoing conversation with the land, both its physical and biological components. Learning what is compatible with soil type, topography, and existing flora and fauna informs appropriate landscape design and dictates the effort required to achieve expectations. For example, the local deer herd mandates that the garden and orchard, as well as most of the small shrub and tree plantings, be fenced-in to survive. Storm water needs to be managed to ameliorate flooding and to foster biological diversity. Planting woody and herbaceous perennials sequesters carbon, builds soil, and adds natural beauty to a landscape that can be, to a large extent, self-managing. Vegetable gardens, fruit orchards, and a pond add a special richness to one’s life. Patience is required because it takes time to learn and appreciate not only what works, but also for things to grow.
A community powered by sunshine
When Oberlin College was founded in 1833, the Oberlin community was an aggregate of homes, buildings, and landscapes that were, by and large, powered by sunshine. It was the default setting?no other choice was readily available. However, living standards were very modest compared to those of the average person in Oberlin today. Nevertheless, even with the changing times, we can realize a future with homes powered by sunshine and local landscapes that provide a large fraction of our food.
Individuals can transform existing or newly constructed houses into positive energy homes with technology and by adopting behaviors consistent with minimal resource use. Condominiums and other multi-unit buildings can be even more effective than single family homes in resource conservation if high performance building standards are met and resident behaviors promote conservation. Off-the-shelf technologies and techniques allow buildings to be powered by the sun at a cost that is essentially the same as conventional construction. Passive solar can provide a large fraction of the energy to heat and light a house for virtually no cost: it is in the design, not the materials. High-performance, quality envelopes and active solar features are investments for stabilizing the climate that also have reasonable payback times, unlike other features we put in our homes that negatively impact climate and have no monetary payback. Of course, aesthetics, beauty, and personal preferences are important because they are frequently the criteria employed in decision-making. People often ask for the economic payback time for a rainwater cistern or a PV system while never considering the payback time for granite counter tops or hot tubs. We need to recognize that selectively making some decisions based solely on payback times stacks the deck against opting for those choices. As a consequence, we have more homes with granite counter tops, hot tubs, and fancy bathrooms than houses with PV systems and rainwater cisterns.
Landscapes of a home and a community can be (re)designed to function like a mature ecosystem that manages water efficiently and creates habitats for numerous life forms, in turn providing resilience to weather extremes. Areas with trees, shrubs, and perennial plants sequester carbon, prevent erosion, clean the air, and are aesthetically pleasing. Local vegetable gardens have many positive attributes. They provide delicious, healthy food. Eating fresh-picked green beans, lettuce, tomatoes, and even zucchini is a sensual delight. When planting, weeding, and harvesting, the gardener is outdoors getting exercise. A garden connects a person to her food and the natural world. It reduces carbon emissions and saves money. Equally important, gardeners gain the satisfaction of growing a portion of their food.
The first home in a community that is powered by sunshine is a curiosity and attracts visitors. Trail Magic, like Hill Top, attracted many visitors?more than a thousand over the course of four years?prompting at least a dozen of them to replicate all or many of Trail Magic’s attributes. In 2013, 150,000 people and 5,000 solar energy sites participated in the American Solar Energy Society’s annual solar tour.23 Likewise, the first public and private landscapes that are designed to mimic natural landscapes or contradict the norm (think front yard vegetable garden) are noticed. When these homes and landscapes are replicated by neighbors, norms shift. In time, it is likely that more resilient, self-sufficient communities will emerge. Is this simplistic projection realistic? Will it alone be enough to create durable communities? I think probably not. Nevertheless, such a path can initiate change and engender connections among neighbors and the biological world, both of which are taking us in the right direction.
Acknowledgments
I thank David Borton, Joe Ferut, Mary McDaniel, David Sonner, Mike Strehle, and Donald Watson for helping create Trail Magic.
